The present invention relates to electrical connectors and in particular to a solder tail alignment and retention system for right angle connectors in which the channels in a solder tail spacer plate have tapered sidewalls through the thickness of the spacer plate and the solder tails, through the region received in the spacer plate are tapered to conform to the tapered sidewalls.
Right angle connectors are typically mounted on a circuit board. A complementary connector mates with the right angle connector in a direction parallel to the circuit board. Contacts in the right angle connector have a mating portion that is parallel to the circuit board and a solder tail that is formed perpendicular to the circuit board on which the connector is mounted. The solder tails are interconnected with circuits on the printed circuit board. The solder tails may be either for surface mount or through hole mount. Surface mount solder tails extend to land interconnected with circuits on the side of the circuit board on which the connector is mounted. Solder tails for through hole mounting extend into plated through holes in the circuit board and are soldered thereto. The array of circuit board through holes or the array of lands for surface mounting have the same pattern and spacing as the solder tails extending from the connector.
Horizontal positioning of connector solder tails has long been important to assure that a mass produced connector having a predetermined solder tail array pattern would be compatible with a mass produced circuit board having a corresponding array of plated through holes or pads. Various approaches have been taken to maintain the solder tails in the desired predetermined array configuration. One approach has been to make connector housings in multiple parts, one of which is a locator plate having an array of apertures corresponding to the pattern and spacing of solder tails extending from the mounting face of the connector. After all of the contacts are inserted into the connector housing, the locator plate is passed over the solder tails from the ends thereof and secured to the connector housing as disclosed in U.S. Pat. No. 4,080,041. In this typical spacer plate, each solder tail is received in a respective aperture in the locator plate.
Where the locator plate is integral with the insulative housing of the connector, another approach such as a slotted locator plate may be used. There are variations to this design. With contacts inserted into contact receiving passages in a connector, solder tails may be bent into the slots of the locator plate to form a right angle with respect to the mating portion of the contacts. U.S. Pat. No. 4,210,376 discloses such a right angle connector in which contacts adjacent to their lower ends are provided with retaining lances. The lances are received in recesses in the sidewalls of the channels of the spacer plate to retain the contacts in the channels. When drawn wire contacts are used alternately deep and shallow channels may be used. The channels have extremely narrow entrance portions and enlarged inner ends. The inner ends should be dimensioned to accommodate the wire conductors and the narrow entrance portions should have a width such that the conductors must be forced into the channels.
U.S. Pat. No. 3,493,916 discloses a right angle connector having a plurality of terminals which have a rearward end portion extending through either a first series of relatively long slots or a second series of relatively short slots in a rearwardly extending flange portion of the connector. U.S. Pat. No. 4,491,376 employs a slotted locator plate in which the slots are narrower in width than the solder tails. Each slot is aligned vertically with a contact receiving passage in both rows of contact receiving passages. Each slot has two detents formed by recesses in the otherwise parallel walls of the locator plate slots. The lower row of solder tails is bent about an anvil and forced into the forward detents in the locator plate slots. Subsequently, the upper row of solder tails is bent and forced into the rear detents of the locator plate slots.
U.S. Pat. No. 4,789,346 discloses a right angle connector having a solder post alignment and retention system in which contacts are inserted into all of the contact receiving passages in a row simultaneously. Concurrently therewith the solder posts are inserted into alternate profiled channels in the solder post spacer plate. As the solder posts are inserted into the channels, the portion of the post spacer plate between adjacent channels deflect laterally with a different effective beam length for each row of contacts inserted. The contacts seat in detents in respective channels.
Vertical position, although important, has been inspected upon manual mounting of a connector on a circuit board to assure that solder tails extend beyond the printed circuit board a sufficient distance to provide a good solder joint. With the advent of robotic installation of connectors on printed circuit board, maintaining the vertical position of solder tails such as during shipping and handling as well as stuffing onto the board is more critical. For robotic assembly it is important to know precisely where each feature of a connector assembly is relative to a datum reference on the connector assembly. The location of an important feature is the end of the solder tails to assure that during robotic stuffing of a printed circuit board the solder tail ends enter a corresponding array of plated through holes in a circuit board. Should the solder tails ride up during insertion of the solder tails into the array of through holes, such as due to stubbing, frictional engagement between a solder tail and a through hole, or due to a centering action as the tapered end of a solder tail is urged toward the center of a through hole, a sufficient length of the solder tail may not extend beyond the lower surface of the printed circuit board to provide an acceptable solder joint.
For example, for a 0.062 inch thick circuit board the solder tails should extend approximately 0.062 inches below the board for soldering. During assembly of a connector, the tip of the solder tails are therefore positioned 0.125 inches below the housing mounting face with an allowance for a tolerance to assure that the solder tails will extend beyond the circuit board an appropriate distance for an acceptable solder joint.
U.S. Pat. No. 4,842,528 discloses a right angle connector having solder tail receiving channels in the spacer plate thereof. The solder tails have stop means extending outwardly from the solder tails below, or both above and below, the spacer plate to prevent the solder tails from moving axially in the direction of the solder tail through the spacer plate. In this manner, the solder tail ends are maintained in a known position.
Molding a plastic article in a mold typically has necessitated that a slight angle be placed on molded surfaces to allow the molded article to be removed from the mold. This angle, called a draft angle, is small and typically on the order of one half degree to one degree. Prior art spacer plates had this typical draft angle formed in solder tail receiving channels therein through the thickness of the spacer plate. The solder tails received in the channels were manufactured such that they were substantially uniform in cross section through the region received in the spacer plate, with the result that the solder tail engaged the channel walls near that surface of the spacer plate where the channels were narrower due to the draft angle when the spacer plate channels were molded. In this manner, any frictional engagement between the channel walls and solder tails to prevent vertical movement of the solder tails through the spacer plate was typically through less than the entirety of the thickness of the spacer plate. The present invention is directed to providing a solder tail retention system for maintaining solder tails in a predetermined position relative to a solder tail spacer plate to prevent vertical movement of solder tails once assembled into the connector. This is achieved by providing angled walls in the spacer plate channels, at least through the regions of the channels where the solder tails are positioned in the assembled connector, and shaping the solder tails through the region received in the spacer plate to conform to the angled channel walls.